Expansion of the automatic fibre analysis by means of SEM/EDX to special fibres (inorganic material fibres)

Project No. BIA 1062

Status:

completed 12/2001

Aims:

The Ordinance on Hazardous Substances classifies man-made mineral fibres according to their carcinogenic characteristics, and requires that they be assessed differently at the workplace in accordance with this classification. In particular, it may be necessary in practice to assess exposure to dust of fibres from different classes. This requirement must be taken into account by the analytical method employed. The proportion of material fibres among the fibre analyses commissioned has increased rapidly over the last one to two years. Experience to date shows that the analysis of an air sample may involve a large number of materials (material fibres), which can rapidly lead to confusion. This drawback is accompanied by other, well-known disadvantages typical of such methods (subjective influences, labour-intensive nature). The objective of this project is therefore to develop further the computer-aided aspect of the analysis.

Activities/Methods:

Based on the experience and expertise gained by the BG Institute for Occupational Safety (BIA) during development of the AutoREM program for automation of fibre analysis by SEM/EDXA, the field of application of this program is extended to the analysis of material fibres. For this purpose, spectra of the materials supplied are stored in a temporary database as reference spectra for each air sample, and treated in the same way as the reference spectra in the standard database, i.e. compared by means of chi square tests and other tests for the goodness of fit with the unknown spectra of the fibrous particles found in the air sample. The remainder of the procedure, in particular the image analysis routines, can largely be retained. The program routine InitProdukt has been developed in addition, which supports the preparation of a reference database for each product and which smoothes and standardises the reference spectra.

Results:

The developed extension of the program is increasingly used for the routine analysis of material fibres.